Well, seeing as the Mile Marker never really took off and now they have resorted to selling electrics, it kinda gives you an idea of how the market feels towards them.
That's not to say that hydraulic winches in general are crap in fact most are used on industrial applications. Although the last few tow trucks I've seen used Ramsey electrics.
There are a few hidden costs to a hydraulic, the main one being the pump. A stock pump barely cuts it. It's not really an option but rather a necessity to buy an upgraded pump.
I've never dealt with Mile Markers Customer Service but I'd check into that too. Warn seems to have one of the best Customer Service in the business. This was one of the reason I went with a Warn over a Ramsey, Superwinch or Mile Marker. Most of the guy's I now run Warns. Although one has had a Mile Marker sitting in his garage for years now. A Warn sits on his Jeep.
Oh and there is even a FAQ page on winches.